ALKOXYPHENYLGLYOXALS AS FLUOROGENIC REAGENTS SELECTIVE FOR GUANINE AND ITS NUCLEOSIDES AND NUCLEOTIDES IN LIQUID-CHROMATOGRAPHY

Glyoxal analogues which have a phenyl moiety substituted with electron -donating methoxyl group(s) or a methylenedioxyl group, react selectiv ely with guanine and its nucleosides and nucleotides in phosphate buff er (pH 7.0) at 37 degrees C for 5-7 min to give the corresponding fluo rescent derivatives. The derivatives can be separated by reversed-phas e liquid chromatography. 3,4-Dimethoxyphenylglyoxal is most sensitive; the detection limits (S/N = 3) for guanine and its nucleosides and nu cleotides vary in the range 40-400 fmol per injection volume depending on the guanine-related compounds.